Thank you both guys of you for the tips :-).
Yes it is about "run as root" and 4MLinux please.
I'm sorry for everything which I wrote abowe does not appear to be relevant to the question.
I was trying to give right away as many info as need 'cos - of course I did not find answers on the internet before I wrote here.
There's no such a files (or similar to any as abowe):
user-dirs.defaults
user-dirs.dirs
in whole installed system.
The /etc/passwd file shows me the "Home directory" - the absolute path to the user’s home directory.
OK, I dis some web search and I will try to add in it:
Documents:x:0:0
ocuments:/dev/sda3/Documents:/usr/sbin/nologin
Downloads:x:0:0
ownloads:/dev/sda3/Documents/Downloads:/usr/sbin/nologin
Music:x:0:0:Music:/dev/sda3/Documents/Music:/usr/sbin/nologin
Pictures:x:0:0:Pictures:/dev/sda3/Documents/Pictures:/usr/sbin/nologin
Screenshots:x:0:0:Screenshots:/dev/sda3/Documents/Pictures:/usr/sbin/nologin
Videos:x:0:0:Videos:/dev/sda3/Documents/Videos:/usr/sbin/nologin
I don't wanna change USER or HOME directory - I just wanna set default folders:
Documents
Downloads
Music
Pictures
Screenshots
Videos
... to another disk (sda3, ntfs).
Or should I - instead of changing defaulth paths - erase those folders and just do-set symlinks which will leads to another /disk/folder?